Geno, the 3 1/4" chambered eight bore is probable the most common length for 8's here in Britain and that would equate to 80mm. Is there much use of 8 bores for wildfowl in Russia and can you get the ammo? There are a couple of custom ammunition makers here in Britain who will supply it but most 8 bore owners make it themselves for Industrial cases as I do. Lagopus.....